Entergy wants its utilities to join the Midwest Independent Transmission System Operator, or MISO. The Carmel, Ind.-based group directs movement of electricity in parts of 11 Midwestern states and Canada's Manitoba province.

Friday's approval could help the electric utility to win nods from remaining regulators. Texas regulators approved the deal Thursday and Louisiana approved it earlier. Entergy still needs blessings from Mississippi and New Orleans city officials.

Joining MISO is supposed to save Entergy customers $1.4 billion over 10 years. MISO says it will ensure Entergy customers get the cheapest possible power. It could also ease complaints that Entergy has used its grid to favor its own power plants over independent generators.